panel.superpose {lattice} | R Documentation

## Panel Function for Display Marked by groups

### Description

This is an useful panel function for trellis displays. Uses a grouping variable, plotting the `x` (and `y` where appropriate) variables with different graphical properties for each distinct value of the grouping variable.

### Usage

    panel.superpose(x, y, panel.groups = "panel.xyplot", subscripts, groups, type="p", ...)
    panel.superpose.2(x, y, subscripts, groups, type="p", ...)

### Arguments

`x,y` | coordinates of the points to be displayed
`panel.groups` | the panel function to be used for each group of points. Defaults to `panel.xyplot` (behaviour in S)
`subscripts` | subscripts giving indices in original data frame
`groups` | a grouping variable. Different graphical parameters will be used to plot the subsets of observations given by each distinct value of `groups`. The default graphical parameters are obtained from `superpose.symbol` and `superpose.line` using `trellis.par.get` wherever appropriate

`type`

character vector specifying what should be drawn for each group. See `panel.xyplot` for details of what the values can be. This is meaningful for `panel.superpose` only when `panel.groups` is `panel.xyplot`.
The 2 functions `panel.superpose` (with `panel.xyplot`) and `panel.superpose.2` differ only in the way the `type` argument is interpreted. For the former, the interpretation is the same as for `panel.xyplot` for each of the unique groups. For the latter, the `type` vector is replicated to be as long as the number of unique values in `groups`, and the points corresponding to the different groups are plotted according to the corresponding type.
See `xyplot` documentation for an example.

`...` | other arguments (mostly graphical parameters, replicated to be as long as the number of groups), ultimately passed down to `panel.xyplot`. In particular, colour can be specified using 3 arguments (`col, col.line, col.symbol`), as in `panel.xyplot`.

### Author(s)

Deepayan Sarkar deepayan@stat.wisc.edu (`panel.superpose.2` contributed by Neil Klepeis)

### See Also

Different functions when used as `panel.groups` gives different types of plots, for example `panel.xyplot`, `panel.dotplot` and `panel.linejoin` (This can be used to produce interaction plots).

### Examples

    data(barley)
    dotplot(variety ~ yield | site, barley, groups = year,
            layout = c(1, 6), aspect = .5,
            col.line = c("grey", "transparent"),
            panel = "panel.superpose",
            panel.groups = "panel.dotplot")

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